Monster Home SQ build
01-09-2010, 09:31 PM
#31
500 Watt CAFz'r
Join Date: Jan 2008
Posts: 537
Right. Having a software compatibility issue between by brain & hands.
High-value, heavy gauge inductor in series to take off the bottom end of the system.
Lots of wire in series = high insertion loss. Generally thought to be an inadvisable approach in crossover design. Certainly, there will be exceptions.
Fozz, main brunt of the question referred to crossover topology. Once you've made your driver measurements & determined enclosure format, what do you use to determine component values relative to the passive crossover components?
I've used LEAP/LMS, CASD/CACD, LFDES/FLTDES and the ever-unfriendly CALSOD.
Each one has benefits & drawbacks, too numerous to list in a reasonable amount of space.
Just curious what others are using in their design kitchen. Lotsa ingredients and recipes available these days. It's a great time to be involved in this area of audio!
High-value, heavy gauge inductor in series to take off the bottom end of the system.
Lots of wire in series = high insertion loss. Generally thought to be an inadvisable approach in crossover design. Certainly, there will be exceptions.
Fozz, main brunt of the question referred to crossover topology. Once you've made your driver measurements & determined enclosure format, what do you use to determine component values relative to the passive crossover components?
I've used LEAP/LMS, CASD/CACD, LFDES/FLTDES and the ever-unfriendly CALSOD.
Each one has benefits & drawbacks, too numerous to list in a reasonable amount of space.
Just curious what others are using in their design kitchen. Lotsa ingredients and recipes available these days. It's a great time to be involved in this area of audio!
Which software do you prefer? In terms of features and being user friendly?
01-10-2010, 01:49 AM
#32
50 Watt CAFz'r
Join Date: Mar 2006
Posts: 50
So, I was assuming that somewhere in the midst of my ramblings, I indicated that the MBL used a passive high-pass on the woofer. In reviewing my prior posts, I can see that..................sorry, I forgot what I was talking about.
Given that the speaker system in question is a three-way, I should have clairified that, the passive high-pass which the amplifier first encounters on its way to the drivers, is a passive band-pass filter. In its simplest topology, this would involve a series capacitor, followed by a series inductor. In the event that the mid and high frequency drivers have anything over 85db/w/m sensitivity, they would have to be attenuated, again by passive components, to combine acceptably well with the low frequency (if you consider +50hz low)
So to further fuel my rant against massive insertion loss, you now have the albeit slight ESR of a capacitor, combined with the significant loss presented by the monster-sized inductor. Add to this the resistive attenuation necessary to bring the mid-high levels in line with the woofer, and you might begin to appreciate why I was underwhelmed by the price
erformance ratio of this system.
Damn, I didn't mean to hijack this thread!
Just wondered what Fozz uses for his design basics.
For the record, I use LEAP as first choice, FLTDES for quick & dirty ballpark stuff, and CALSOD if I'm feeling particularly masochistic.
Anyone remember using the early version of LEAP? (DOS prompt architecture)
Yes, that's my "Old-fart-itis" kicking in. Off for a swig of RedBull & Geritol................................
Given that the speaker system in question is a three-way, I should have clairified that, the passive high-pass which the amplifier first encounters on its way to the drivers, is a passive band-pass filter. In its simplest topology, this would involve a series capacitor, followed by a series inductor. In the event that the mid and high frequency drivers have anything over 85db/w/m sensitivity, they would have to be attenuated, again by passive components, to combine acceptably well with the low frequency (if you consider +50hz low)
So to further fuel my rant against massive insertion loss, you now have the albeit slight ESR of a capacitor, combined with the significant loss presented by the monster-sized inductor. Add to this the resistive attenuation necessary to bring the mid-high levels in line with the woofer, and you might begin to appreciate why I was underwhelmed by the price
erformance ratio of this system.Damn, I didn't mean to hijack this thread!
Just wondered what Fozz uses for his design basics.
For the record, I use LEAP as first choice, FLTDES for quick & dirty ballpark stuff, and CALSOD if I'm feeling particularly masochistic.
Anyone remember using the early version of LEAP? (DOS prompt architecture)
Yes, that's my "Old-fart-itis" kicking in. Off for a swig of RedBull & Geritol................................
01-16-2010, 04:20 PM
#33
Guest
Posts: n/a
Yee of little faith. You always seem to have a negitive pull on everything. This is not the fist speaker that I've built, and I take it very seriously. Crossover design is not simple, nor would you hear me say it is. But let's just say I have friends in high places. I've already had measurments done on the speakers, but to be honest, I had a pretty good idea where the crossover points were going to be when I started. And just to be clear, speaker design is just as much art as it is science and measurements. Software will never tell you how a speaker sounds, but I though you already knew that!
01-16-2010, 06:41 PM
#34
Yankee
Join Date: Oct 2003
Posts: 3,599
A steep cutoff is not always better. This particular design is using 6db per octave slopes.
I have tried active filters as a bench mark to help pinpoint frequencies. But in the end, the passive systems react differently and sound differently than active. So most of the work was waisted.
I have tried active filters as a bench mark to help pinpoint frequencies. But in the end, the passive systems react differently and sound differently than active. So most of the work was waisted.
Most commercial speakers dont use the steep slopes but I think Joseph speakers do (didnt Joseph used to be Infinite Slope?)and they sound wonderful. A number of manufacturers like gentle 6db slopes for phase response reasons (doent it also maximise efficiency too?)... I dont know I am sure every driver demands considerations as to what slope is best.
So, what do you use, (apart from ears & experience) to determine the value of your x-over components?
It's one of the most arcane and dark areas of the audio arts, so I'm always intrigued by what folks are using.
One of the most disappointing speakers I've heard, is the MBL mini-monitor. I found out that they actually use a passive high-pass filter before the woofer. So a heavy-gauge inductor is the first series component between the amp and drivers. Could explain that sub-83db sensitivity figure. Generally, the MBL stuff I've heard has been very good, but way too rich for my bank account. These ones seemed to have been designed on an off day........
It's one of the most arcane and dark areas of the audio arts, so I'm always intrigued by what folks are using.
One of the most disappointing speakers I've heard, is the MBL mini-monitor. I found out that they actually use a passive high-pass filter before the woofer. So a heavy-gauge inductor is the first series component between the amp and drivers. Could explain that sub-83db sensitivity figure. Generally, the MBL stuff I've heard has been very good, but way too rich for my bank account. These ones seemed to have been designed on an off day........
01-16-2010, 07:31 PM
#35
Defro,
All the speakers were measured individually. Not just frequency response, but the T/S parameters as well. I do not do the measurement personally; I have a retired engineer do it for me. He also modifies my crossovers and makes suggestions on how to improve my cabinet designs. This is was he did for a living, so I trust his judgement.
These speakers are for a friend of mine, so they are getting much more work than usual.
All the speakers were measured individually. Not just frequency response, but the T/S parameters as well. I do not do the measurement personally; I have a retired engineer do it for me. He also modifies my crossovers and makes suggestions on how to improve my cabinet designs. This is was he did for a living, so I trust his judgement.
These speakers are for a friend of mine, so they are getting much more work than usual.
01-16-2010, 08:02 PM
#36
50 Watt CAFz'r
Join Date: Mar 2006
Posts: 50
Tad
Hey Johnny Vroom,
We're on the same page. The local (Hong Kong) TAD distributor is a friend of mine. Gives me great deals on the pro drivers. I've ended up using a dozen or so of the now-discontinued 1201 mid-bass as guitar speaker. Kept a couple of them around for one of my own projects. Their show-room is a thing of wonder and beauty.
The mini MBL monitor stands out in my mind as a poorly designed niche product, and yes, their big stuff, while looking unlike anything else, also succeeds in sounding like nothing I want to listen to.
Fozz, keep the photos & updates coming. It's always interesting to see a non-car audio thread on this forum.
Dave, give me a PM if you've got time.
We're on the same page. The local (Hong Kong) TAD distributor is a friend of mine. Gives me great deals on the pro drivers. I've ended up using a dozen or so of the now-discontinued 1201 mid-bass as guitar speaker. Kept a couple of them around for one of my own projects. Their show-room is a thing of wonder and beauty.
The mini MBL monitor stands out in my mind as a poorly designed niche product, and yes, their big stuff, while looking unlike anything else, also succeeds in sounding like nothing I want to listen to.
Fozz, keep the photos & updates coming. It's always interesting to see a non-car audio thread on this forum.
Dave, give me a PM if you've got time.
01-17-2010, 05:59 PM
#40
0 Watt CAFz'r
Join Date: Sep 2009
Posts: 24
87-90 db is pretty typical for home loudspeakers. Most home systems are in the 100 watt per channel range so you're around 108 db max at 1m not including any room effects. This is decently loud for most people for midrange and highs - lows are another matter.
Scott
Scott
